The long-term objective of the proposed research is to develop, qualify for an IDE, conduct clinical trials, obtain PMA and market an implantable temporary ventricular assist system (VAS) which is superior to existing devices with respect to size, surgical complexity, ease of use and cost. The principal specific aim of the proposed program is to develop and demonstrate the continuous delivery VAS which is based on Phase I results and Nimbus sponsored developments. The device is targeted for the temporary ventricular assist market. The goals will be achieved by fabricating development devices, conducting performance, flow visualization and hemolysis tests and conducting acute and chronic in vivo tests. The in vivo tests will evaluate hemolysis and thrombogenicity characteristics, device-host interactions and demonstrate suitability of the device for moderate term use. Laboratory endurance testing of the device will also be accomplished. The technological innovation involves demonstration of a compact continuous delivery VAS which resolves shaft seal and thrombus problems characteristic of previous devices of this type and which retains required performance and hemolysis characteristics. The commercial potential lies in its superiority to currently available implantable devices with respect to size, complexity of surgical implantation, ease of use and cost.